The present application relates to weather radar systems. More particularly, the present application relates to a weather radar system that displays the presence of weather on a screen.
U.S. Pat. No. 6,424,288 invented by Daniel L. Woodell and assigned to the assignee of the present application discloses systems for and methods of displaying radar information using weather radar systems. Weather radar systems generally include an antenna, a receiver/transmitter circuit, a processor, and display. The processor is coupled between the display and the receiver/transmitter circuit. The receiver/transmitter circuit is coupled between the processor and the antenna.
The processor provides transmit signals through the receiver/transmitter circuit to the antenna to transmit radar beams. The processor receives radar return signals derived from radar returns received by the antenna. The radar return signals are provided to the processor via the receiver/transmitter circuit.
Conventionally, pilots use weather radar systems to detect and avoid hazardous weather. The radar return signals are processed to provide graphical images to a radar display. The radar display is typically a color multi-function display (MFD) unit that provides color graphical images to represent the severity and location of weather. Some aircraft weather radar systems also include other hazard detection systems such as a turbulence detection system. The turbulence detection system can provide indications of the presence of turbulence or other hazards. Conventional weather radar systems include those manufactured by Rockwell Collins, Inc., Honeywell International, Inc. and others.
U.S. Pat. No. 6,879,280, assigned to the assignee of the present invention, discloses an aircraft weather radar system. The system displays storm system characteristics on a vertical profile display. Uncertainty associated with storm tops can be displayed. The uncertainty can be related to a prediction of the altitude of the storm top when the aircraft reaches the location of the storm top.
According to another conventional system, turbulence regions detected by airborne weather radar are displayed using colored graphics in the form of amorphous areas (e.g., “blobs”) for directly detected turbulence on a position plan display. A reasonable first order estimate for convective weather is the entire cloud mass contains turbulence that is hazardous. This is a typical turbulence avoidance method used by aircraft crews. Flying over convective weather produces a smoother, less hazardous ride that flying through convective weather. The areas or blobs of magenta color can often represent regions of inferred potential turbulence outside of the region of directly detectable turbulence. The uncertainty associated with hazard areas, such as these types of blobs has not been shown.
Heretofore, conventional weather radar systems are only able to produce uncertain hazard assessments for longer ranges. The uncertainty of those assessments is driven by the variableness of weather, the extreme low level radar returns in environments such as the tops or sides of conductive weather, and the vertical beam width inherent in weather radar systems. This uncertainty affects the display of hazards in the plan view, range/height displays and the potential panoramic (angle/angle) displays. Displaying hazards when the hazard is not necessarily accurately sensed can cause a flight crew to fly closer to a hazard or avoid a hazard that does not exist.
According to one example, if a conventional radar display displays a hazard at a long distance, a pilot using the display desires to determine if the current flight path is over the top of the hazardous weather in route. Given a 3.5 degree beam width in elevation on a conventional weather radar installation, the beam width is 35,000 feet at a 100 nautical mile range. Conventional weather radar systems have been able to effectively reduce the 35,000 foot beam width via signal processing techniques, but the amount of uncertainty can still be in the 10,000 foot range. Since uncertainty decreases with decreasing range to a weather target, hazardous regions above detectable convective cells may be detected later than desired forcing aircrews to make very late non-optimum avoidance maneuvers and may even cause periodic inadvertent thunderstorm penetrations. An uncertainty of 10,000 feet can also cause periodic unnecessary deviations if regions that have an uncertain risk assessment are found to be not hazardous as range decreases.
Thus, there is a need for a weather radar display that indicates errors associated with the display of hazards at longer ranges. Further still, there is a need for a weather radar display utilizing a plan view and range/height display configuration that provides an indication of uncertainty associated with weather height. Further still, there is a need for iconal representation that extends above a sensed weather hazard and indicates the uncertainty associated with the sensing of the weather hazard. Further still, there is a need for representing uncertainty associated with detected weather by utilizing density modulation, display dithering, or embedded recognizable patterns. Yet further there is a need to identify two cases of uncertainty: 1. uncertainty displayed by itself, and 2. regions that are hazardous and can be grown to include possible regions of hazard that have not been directly detected and displayed because of the possible uncertain nature of the hazard or measurement of the hazard.
It would be desirable to provide a system and/or method that provides one or more of these or other advantageous features. Other features and advantages will be made apparent from the present specification. The teachings disclosed extend to those embodiments which fall within the scope of the appended claims, regardless of whether they accomplish one or more of the aforementioned needs.